The invention concerns a self-emptying centrifuge drum with an intake for the centrifugate, a peeling chamber that accommodates a peeling disk for diverting the clarified liquid, and an automatic device that senses the level of solids in the separating space of the drum and that consists of channels extending from the separating space to another peeling chamber with another peeling disk, whereby the outflow channel from the second peeling disk communicates with a measuring instrument that operates in conjunction with controls that introduce the extracted solids into the drum.
A centrifuge drum of this type is known from German Pat. No. 2 926 237. It is employed to initiate automatic incomplete or complete emptying processes in the drum once a prescribed volume of solids has accumulated in the separating space of the drum. For this purpose a slight proportion of water is constantly diverted into a peeling chamber having a peeling disk through one or more channels extending from the separating space while clarification is proceeding in the drum. The liquid deriving from the peeling disk s supplied to a measuring instrument, a flowmeter for example. The flowmeter is connected to controls that initiate complete or incomplete emptying of the drum when the flow through the flowmeter decreases below a certain threshold. The flow through the flowmeter decreases when enough centrifuged solids have accumulated in the separating space to block the channels.
It is known that centrifuge drums of this type cannot be employed with all types of solids. There are solids that never become dense enough to block the channels. The signal for initiating incomplete or complete emptying will arrive either too late or not at all. The channels are particularly difficult to block with bacterial suspensions, and the solids are likely to arrive in the second peeling chamber along with the extracted liquid through the channels and be diverted out over the peeling disk accommodated therein.